Haemophilus influenzae B (HiB)

Haemophilus influenzae, often referred to as H. flu
or "HiB" for convenience, is a family of bacteria all of which can
cause diseases in people. (The bacteria does not have anything
to do with influenza,
but when first identified in 1892 it was thought to cause the flu,
hence the name.) There are six types of H. flu known;
most H. flu-related disease is caused by type B, or "HiB".

Until a vaccine for HiB was developed, HiB was one of the two most
common causes of otitis
media, sinus infections, and bronchitis. More important, HiB
was also the most common cause of
meningitis,
and a frequent culprit in cases of pneumonia, septic arthritis (joint
infections), cellulitis (infections of soft tissues), and pericarditis
(infections of the membrane surrounding the heart). One of the most
dangerous results of HiB infection was epiglottitis, an infection of
the "flap" at the top of the windpipe that can kill a child by blocking
airflow to the lungs.

Before the vaccine was introduced, there were about 20,000 serious cases
of HiB infections in the United States every year, most of which were
of meningitis. Since the vaccine became required, that number has dropped
to about one-sixth to one-eighth of what it was. HiB infections are very
rare after age 5 years except in people with immune-system problems.
Before we were able to vaccinate against it, 1 out of 200 children had
severe HiB infections, while two-thirds of HiB infections happened in
children less than 18 months old. In some countries, serious HiB
infections have almost disappeared, thanks to the vaccine.

HiB vaccine is given 2-3 times in the first 6 months of life, followed by
a single dose at age 12-18 months. (There are three different HiB vaccines
available; they are all very effective, but the dosage schedule differs
between the types.) There is also a vaccine,
COMVAXTM, which combines the HiB and
hepatitis B
vaccines; the schedule for this vaccine is slightly different
because HiB vaccine does not work well if it is given before age 2 months,
while hepatitis B can be started earlier.)

PLEASE NOTE: As with all of this Web site, I try to give
general answers to common questions my patients and their parents ask me
in my (real) office. If you have specific questions about your
child you must ask your child's regular doctor. No doctor can give
completely accurate advice about a particular child without knowing and
examining that child. I will be happy to try and answer
general questions
about children's health, but unless your child is a regular patient of
mine I cannot give you specific advice.